Focused aperture module
First Claim
1. A particle analyzing apparatus for detecting properties of particles, said particle analyzing apparatus including a container for holding a liquid suspension of the particles to be analyzed, a first liquid holding chamber, a flow director having a bore which forms a liquid passageway between said container and said first chamber, a second liquid holding chamber, aperture means including a sensing aperture which forms a constricted liquid and electrical passageway between said first chamber and said second chamber, means for providing an electrical current through said sensing aperture to generate detectable electrical signals with the passage of the particles through said sensing aperture, fluid moving means for providing a pressure drop across said sensing aperture to move a quantity of liquid from said first chamber to said second chamber, means for providing a particle free liquid to said first chamber to form a liquid sheath around a quantity of said liquid suspension from said flow director, the improvement comprising:
- means for providing a substantially constant pressure drop across said flow director to move said quantity of said liquid suspension from said container to said first chamber, whereby said substantially constant pressure drop establishes a substantially constant flow rate of said liquid suspension through said sensing aperture;
said bore of said flow director having an elongated configuration dimensioned to form a fluid resistor for limiting the flow of said quantity of said suspension through said bore, whereby said fluid resistor sufficiently restrains the flow therethrough to a desired flow rate so as to allow for said pressure drop across said flow director to be of a magnitude that is subject to regulation and measurement.
1 Assignment
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Accused Products
Abstract
A particle analyzer for a sample suspension of particles originating in a container in which: a flow director is mounted between the container and a first chamber, a particle sensing aperture is mounted between the first chamber and a second chamber, a liquid sheath is introduced into the first chamber for hydrodynamically focusing the particles through the sensing aperture, an electrical current passes through the sensing aperture for generating impedance signals, the pressure drop is regulated across the flow director to assure a constant flow of the suspension through the flow director and the aperture, and the flow director is formed into an optical element for viewing the sensing aperture.
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Citations
14 Claims
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1. A particle analyzing apparatus for detecting properties of particles, said particle analyzing apparatus including a container for holding a liquid suspension of the particles to be analyzed, a first liquid holding chamber, a flow director having a bore which forms a liquid passageway between said container and said first chamber, a second liquid holding chamber, aperture means including a sensing aperture which forms a constricted liquid and electrical passageway between said first chamber and said second chamber, means for providing an electrical current through said sensing aperture to generate detectable electrical signals with the passage of the particles through said sensing aperture, fluid moving means for providing a pressure drop across said sensing aperture to move a quantity of liquid from said first chamber to said second chamber, means for providing a particle free liquid to said first chamber to form a liquid sheath around a quantity of said liquid suspension from said flow director, the improvement comprising:
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means for providing a substantially constant pressure drop across said flow director to move said quantity of said liquid suspension from said container to said first chamber, whereby said substantially constant pressure drop establishes a substantially constant flow rate of said liquid suspension through said sensing aperture; said bore of said flow director having an elongated configuration dimensioned to form a fluid resistor for limiting the flow of said quantity of said suspension through said bore, whereby said fluid resistor sufficiently restrains the flow therethrough to a desired flow rate so as to allow for said pressure drop across said flow director to be of a magnitude that is subject to regulation and measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. For use in a particle analyzing apparatus of the Coulter type in which a particle sensing aperture provides the only fluid and electrical current paths between a body of liquid in a first chamber and a body of liquid in a second chamber, a sample suspension being caused to flow through said sensing aperture and into said second chamber;
- said apparatus also including a bore opening from a container into said first chamber for receiving the flow of sample suspension, particle free liquid being supplied into said first chamber for sheathing said flowing sample suspension as it passes from said bore;
the improvement comprising, means for providing a relatively constant pressure drop across said bore to move said sample suspension from said container to said first chamber, whereby said substantially constant pressure drop establishes a substantially constant flow rate of said sample suspension through said sensing aperture;
said bore being dimensioned to form a fluid resistor for limiting the flow of said sample suspension through said bore.
- said apparatus also including a bore opening from a container into said first chamber for receiving the flow of sample suspension, particle free liquid being supplied into said first chamber for sheathing said flowing sample suspension as it passes from said bore;
Specification